In recent years, a silicon carbide semiconductor device has made progress toward practical utilization as a power semiconductor device. This is because the use of a silicon carbide material for a semiconductor device is expected to increase breakdown voltage and reduce on-resistance as compared to a currently predominant semiconductor device made of a silicon material. In the process of manufacturing such a silicon carbide semiconductor device, a semiconductor substrate is doped with an impurity by an ion implantation process, for example (see Japanese Patent Laying-Open No. 2001-68428 (PTD 1), for example).